Revised Final Report - Confirmatory Survey of the ...job hazard analysis kiloelectron volt kilometer square meter Mixed Analyte Performance Evaluation Program ... radiation research,

HO RI S E

OAK RIDE INSTITUTE FOR SCIENCE AND EDUCATION

August 23, 2005

Mr. Thomas DragounNRR/DRIPU.S. Nuclear Regulatory Commission475 Allendale RoadKing of Prussia, PA 19406

SUBJECT: REVISED FINAL REPORT-CONFIRMATORY SURVEY OF THEUNIVERSITY OF VIRGINIA REACTOR, UNIVERSITY OF VIRGINIA,CHARLOTTESVILLE, VIRGINIA [DOCKET NO. 50-62; TASK NO. 2.10]

Dear Mr. Dragoun:

The Environmental Survey and Site Assessment Program (ESSAP) of the Oak Ridge Institute forScience and Education (ORISE) performed confirmatory survey activities of the University ofVirginia Research Reactor in Charlottesville, Virginia during the period March 8 to 10, 2005.Enclosed is the subject revised final confirmatory survey report with NRC/NRR commentsincorporated.

If you have any questions please contact me at (865) 576-3356 or Alex J. Boerner at (865) 574-0951.

Sincerely,

Timothy J. BauerHealth PhysicistEnvironmental Survey and

Site Assessment Program

TJB:ar

Enclosure

cc: A. Adams, NRC/NRR/OWFN 12G13S. Adams, NRC/NRR/OWFN 012E5W. Eresian, NRC/NRR/OWFN 012G13D. Hughes, NRC/NRR/OWFN 012G13

E. Abelquist, ORISE/ESSAPA. Boemer, ORISE/ESSAPFile/0981

P. 0. BOX 117, OAK RIDGE, TENNESSEE 37831-0117

Operated by Oak Ridge Associated Universities for the U.S. Department of Energy

to

to

REVISED FINAL REPORT

CONFIRMATORY SURVEYOF THEUNIVERSITY OF VIRGINIA REACTORUNIVERSITY OF VIRGINIACHARLOTTESVILLE, VIRGINIA

T. J. BAUER

PreparedU.S. NuOffice o0

for theclear Regulatory Commissionf Nuclear Reactor Regulation

Agendes and their conractors; other requests shallappmved by the ouiginating faclity or higher DOEprogrammatic authority.

The Oak Ridge Institute for Science and Education (ORISE) is a U.S. Department of Energy facility focusing onscientific initiatives to research health risks from occupational hazards, assess environmental cleanup, respond toradiation medical emergencies, support national security and emergency preparedness, and educate the nextgeneration of scientists. ORISE is managed by Oak Ridge Associated Universities. Established in 1946, ORAU isa consortium of 9 icolleges and universities.

NOTICES

The opinions expressed herein do not necessarily reflect the opinions of the sponsoring institutions of Oak RidgeAssociated Universities.

This report was prepared as an account of work sponsored by the United States Government. Neither the UnitedStates Government nor the U.S. Department of Energy, nor any of their employees, makes any warranty, expressedor implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of anyinformation, apparatus, product, or process disclosed, or represents that its use would not infringe on privatelyowned rights. Reference herein to any specific commercial product, process, or service by trade name, mark,manufacturer, or otherwise, does not necessarily constitute or imply its endorsement or recommendation, or favor bythe U.S. Government or any agency thereof. The views and opinions of authors expressed herein do not necessarilystate or reflect those of the U.S. Government or any agency thereof.

ORISE 05-1219

CONFIRMATORY SURVEYOF THE

UNIVERSITY OF VIRGINIA REACTORUNIVERSITY OF VIRGINIA

CHARLOTTESVILLE, VIRGINIA

Prepared by

T. J. Bauer

Environmental Survey and Site Assessment ProgramOak Ridge Institute for Science and Education

Oak Ridge, Tennessee 37831-0117

Prepared for the

U.S. Nuclear Regulatory CommissionOffice of Nuclear Reactor Regulation

REVISED FINAL REPORT

AUGUST 2005

This report is based on work performed under an Interagency Agreement (NRC Fin. No. J-3036)between the U.S. Nuclear Regulatory Commission and the U.S. Department of Energy. OakRidge Institute for Science and Education performs complementary work under contract numberDE-AC05-00OR22750 with the U.S. Department of Energy.

University of Virginia Reactor projects\981\Reports\2005-08-08 Revised Final Report.doc

CONFIRMATORY SURVEYOF THE



Prepared by: 4 4t".. • x.

P a. J. Bar'r, Health PhysicistEnvironmental Survey and Site Assessment Program

Reviewed by: C~ljA. Boemer, Acting Survey Projects ManagerEnvironmental Survey and Site Assessment Program

Reviewed by: YO •LA•R. D. Condra, Laboratory ManagerEnvironmental Survey and Site Assessment Program

-Reviewed by: ) {JAA. T. Payne, Quality ManagerEnvironmental Survey and Site Assessment Program

Reviewed by:E. W. Abelquist, Program D66torEnvironmental Survey and 9ite Assessment Program

Date: / C'

Date: J le) Oas-

Date: ?)I2/0

Date:

Date:

University of Virginia Reactor projects\O981\Reports\2005-08-08 Revised Final Report.doc

ACKNOWLEDGMENTS

The author would like to acknowledge the significant contributions of the following staffmembers:

FIELD STAFF

T. D. Herrera

LABORATORY STAFF

R. D. CondraJ. S. CoxW. P. IveyW. F. Smith

CLERICAL STAFF

D. K. HerreraK. L. PondA. Ramsey

ILLUSTRATORS

T. L. BrownT. D. Herrera

University of Virginia Reactor projects\0981\Reports\2005-08-08 Revised Final Reportdoc

TABLE OF CONTENTS

PAGE

List of Figures .................................................................................................................................. ii

List of Tables ................................................................................................................................. iii

Abbreviations and Acronym s ................................................................................................... iv

Introduction and Site History ....................................... ............................................................... 1

Site D escription ............................................................................................................................... 2

Objectives ....................................................................................................................................... 3

D ocum ent Review ........................................................................................................................... 3

Procedures ....................................................................................................................................... 3

Sam ple Analysis And D ata Interpretation ................................................................................. 6

Findings and Results ....................................................................................................................... 7

Com parison of Results with Guidelines ................................................................................... 10

Summ ary ....................................................................................................................................... 10

Figures ........................................................................................................................................... 12

Tables ............................................................................................................................................ 20

References ..................................................................................................................................... 26

Appendices:

Appendix A: Major Instrumentation

Appendix B: Survey and Analytical Procedures

Appendix C: Summary of Surface Soil Screening Values

University of Virginia Reactm i projects\098r\Reports\2005-OS-08 Revised Final Report.doc

LIST OF FIGURES

FIGURE 1:

FIGURE 2:

FIGURE 3:

FIGURE 4:

FIGURE 5:

FIGURE 6:

FIGURE 7:

PAGE

Location of the University of Virginia, Charlottesville, Virginia ..................... 13

UVA Reactor First Floor-Measurement and Sampling Locations .................. 14

UVA Reactor Mezzanine Floor-Measurement and Sampling Locations ..... 15

UVA Reactor Ground Floor, East Areas-Measurement and SamplingL ocations ................................................................................................................ 16

UVA Reactor Ground Floor, West Areas-Measurement and SamplingL ocations ................................................................................................................ 17

UVA Reactor Ground Floor, Reactor Pool Walls-Measurement andSam pling Locations .......................................................................................... 18

UVA Reactor Pond-Sampling Locations ........................................................ 19

University of Virginia Reactor UV projects\0981\Reports\2005-08-08 Revised Final Report.doc

LIST OF TABLES

TABLE 1:

TABLE 2:

TABLE 3:

PAGE

Surface Activity Levels .................................................................................... 21

Radionuclide Concentrations in Soil-Interior Locations and Reactor Pond ........ 24

Radionuclide Concentrations in Soil-Split Samples from WasteTank Excavation .............................................................................................. 25

University of Virginia Reactor iii projects\J98l\Reports\2005-08-08 Revised Final Report.doc

ABBI9EVIATIONS AND ACRONYM

Ei

Etotalbi

CAVALIER

cmcm,cpmd'

DCGLDOEDPdpmdpmo100 cm2

ESSAPFSSISMISOITPJHAkeVkIn

MAPEPMDCMDCRMeVmminmgmg/cm

2

mmnMWNaINISTNRCNRIPNRRORISEpCi/gRAIS

instrument efficiencysurface efficiencytotal efficiencynumber of background counts in the intervalCooperatively Assembled Virginia Low IntensityEducational Reactorcentimetersquare centimetercounts per minuteindex of sensitivityderived concentration guideline levelU.S. Department of Energydecommissioning plandisintegrations per minutedisintegrations per minute per 100 square centimetersEnvironmental Survey and Site Assessment Programfinal status surveysintegrated safety managementInternational Standards OrganizationIntercomparison Testing Programjob hazard analysiskiloelectron voltkilometersquare meterMixed Analyte Performance Evaluation Programminimum detectable concentrationminimum detectable count ratemillion electron voltsmeterminutemilligrammilligrams per square centimetermillimetermegawattsodium iodideNational Institute of Standards and TechnologyNuclear Regulatory CommissionNIST Radiochemistry Intercomparison ProgramOffice of Nuclear Reactor RegulationOak Ridge Institute for Science and Educationpicocuries per gramrequest for additional informationsecond

University of Virginia Reactor iv projects5981\Repors2005-08-08 Revised Final Reportdoc

ABBREVIATIONS AND ACRONYMS (Continued)

SOF sum-of-fractionsTAP total absorption peakUVA University of VirginiaUVAR University of Virginia Reactor

University of Virginia Reactor V projects\0981\Reports\2005-08-08 Revised Final Reportdoc

CONFIRMATORY SURVEYOFTHE



INTRODUCTION AND SITE HISTORY

The University of Virginia (UVA) operated the University of Virginia Reactor (UVAR)

beginning in 1960 under U.S. Nuclear Regulatory Commission (NRC) License No. R-66 for

radiation research, activation analysis, isotope production, neutron radiography, radiation

damage studies, and training of nuclear engineering students. The UVAR was a light-water

cooled, moderated, and shielded pool-type nuclear reactor. Originally commissioned to operate

at a maximum power of one megawatt (MW), it was upgraded in January 1971 to operate at two

MW. The original fuel was aluminum clad high-enriched uranium, but was converted to low-

enriched uranium in early 1994.

The UVAR was permanently shut down in June 1998 and the fuel was removed by mid 1999.

The integrated power generation of the UVAR was an estimated 2,559 MW-days. A radiological

characterization survey was initiated in July 1999, with the report completed in April 2000.

UVA submitted a Decommissioning Plan (DP) to the NRC in February 2000. Decommissioning

began in March 2002 with the removal of extraneous fixtures, equipment, and materials, such as

the reactor grid plate, reactor support structure, and equipment and activated concrete from the

reactor pool. Final status surveys (FSS) were completed and the results presented to the NRC in

2004 (UVA 2000 and 2004a).

The CAVALIER (Cooperatively Assembled Virginia Low Intensity Educational Reactor) was

operated in the UVAR facility and separately decommissioned. A FSS was performed and a

license termination requested. The CAVALIER facility, NRC License R-123, was added within

the scope of the UVAR facility and included in the FSS (UVA 2004a).

The NRC's Headquarters Office of Nuclear Reactor Regulation (NRR) requested that the Oak

Ridge Institute for Science and Education's (ORISE) Environmental Survey and Site Assessment

Program (ESSAP) perform confirmatory surveys of the UVAR facility.


SITE DESCRIPTION

The UVA is located approximately 0.6 kilometers (kIn) west of the city limits of Charlottesville

in Albemarle County, Virginia (Figure 1). The UVAR facility is located on the northern grounds

of the UVA and includes approximately 2,030 square meters (m2) of interior floor space and

9,390 mi2 of fenced land.

The upper floor (first floor) contains the Reactor Confinement Room (Room 131), which housed

the former UVAR in the 9.8 m long by 3.7 m wide by 8.2 m deep reactor pool. This room also

held associated operating equipment, systems, and controls and is circular in shape with an

elevated ceiling (approximately 10 m). Most of the impacted reactor and support system

components were removed for disposal as radioactive waste or free released. Also located on the

upper floor are the Instrument Shop (Room 128), the Shipping Area (Room 127), and multiple

offices and other support facilities (UVA 2004a).

Below the upper floor is the Mezzanine level which includes the Demineralizer (Room M021),

Mechanical Room (Room M020), HP Laboratory (Room M019), several partially contaminated

laboratories (Rooms M005 and M008), and multiple offices and other support facilities for staff

and students. A crawl space is accessible from the stairwell. Adjacent to the Reactor

Confinement Room, there was a cooling tower located on the roof of the Mezzanine level that

provided cooling for the reactor secondary system water (UVA 2004a).

Below the Mezzanine level is the ground floor. This floor contains the Heat Exchanger (Room

G024), Rabbit Room (Room G005), Beamport/Experimental Area (Room G020), Hot Cell

(Rooms G025, G026, and G027), Counting Room (Room G004), Woodworking and Machine

Shop (Room G008), Source Storage (Rooms G007A, G018, and G022), the former CAVALIER

Facility (Room G007), and miscellaneous support facilities and areas (UVA 2004a).

The fenced land area included several underground tanks. Two of these tanks were used for

collection and holdup of facility discharges containing radioactive contamination and one,

located at ground level at the front of the facility, was used during fuel shipments. Exterior

construction of the UVAR facility is of metal and concrete block with brick veneer; interior

University of Virginia Reactor 2 projects\0981\Reports\2005-08-08 Revised Final Reportdoc

construction includes concrete slab floors and walls of block and drywall (UVA 2000 and

2004a).

OBJECTIVES

The objectives of the confirmatory survey were to provide independent contractor field data

reviews and radiological data for use by the NRC in evaluating the adequacy and accuracy of the

licensee's procedures and final status survey results.

DOCUMENT REVIEW

ESSAP reviewed the licensee's FSS plan (UVA 2004b) and report (UVA 2004a) for adequacy

and appropriateness taking into account the DP (UVA 2000) and MARSSIM guidance (NRC

2000). Data were evaluated to assure that areas exceeding guidelines were identified and had

undergone remediation. Final status survey results were compared with guidelines to ensure that

the data had been interpreted correctly.

PROCEDURES

ESSAP performed confirmatory surveys of the UVAR during the period March 8 to 10, 2005.

The survey was performed in accordance with the site-specific survey plan submitted to and

approved by the NRC and the ORISE/ESSAP Survey Procedures and Quality Assurance

Manuals (ORISE 2005a and 2004b and c). Additional information concerning major

instrumentation, sampling equipment, and survey and analytical procedures may be found in

Appendices A and B.

INTERIOR

ESSAP used the following procedures for the interior portions of the survey.

Reference Grid

Measurement and sampling locations were referenced to the existing UVA-established grid

system.

University of Virginia Reactor 3 projects\0981Reports\2005-08-08 Revised Final Report.doc

Surface Scans

Surface scans for beta and gamma radiation were performed over selected areas of the UVAR

facility as summarized in the table below. Survey areas included areas with high potential for

residual contamination exceeding release criteria, such as the Reactor Confinement Room (Room

131) and adjacent rooms used for reactor operations and laboratories where radionuclides were

used during experiments.

Surface Scan Coverage forUVAR Facility Area Beta and Gamma Radiation

Floors Lower Walls Upper Walls and CeilingsReactor Confinement Room 50% a(Room 131)Reactor Pool 75% 5-10%Former HP Lab (Rooms M005 and 50%M005A) 100% 5%Former Hot Lab (Room M008) 75%Demineralizer Room (Rooms M021 25%and M021A)Rabbit Room (Room G005)CAVALIER Facility (Room G007) 10%Heat Exchanger Room (Room G024) 75%Hot Cell (Rooms G025, G026, and 50-100% 25-50%G027) 50-100% 25-50%

'Not performed

Particular attention was given to remediated and adjacent surfaces, cracks and joints in the floors

and walls, and other locations where residual radioactive material may have accumulated. In

addition to surfaces, the boreholes UVA installed into the reactor pool floor were gamma

scanned. Scans were performed using gas proportional and Nal scintillation detectors coupled to

ratemeters or ratemeter-scalers with audible indicators. Locations of elevated direct radiation

were noted for further investigation.

Surface Activity Measurements

UVA did not determine construction material-specific backgrounds for correcting surface

activity measurements to account for contributions from naturally occurring materials. Instead,

UVA performed a shielded and unshielded measurement at each location to correct for ambient

University of Virginia Reactor 4 projects\0981\Reports\2005-08-08 Revised F'mal Report.doc

gamma background contribution to the measurement count rate. ESSAP direct measurements

were corrected for ambient background using the same methodology.

Direct measurements for total beta activity were performed at 60 locations, chosen judgmentally,

that included areas of elevated direct radiation identified by surface scans. Dry smears were

collected at each direct measurement location for determining removable gross alpha and gross

beta activity, except for six locations measured on the upper walls of the reactor pool which were

not accessible; direct measurements were performed using an extension pole at these locations.

Direct measurements were performed using gas proportional detectors coupled to ratemeter-

scalers. Figures 2 through 6 show measurement locations.

Soil Sampling

Sub-surface soil samples were collected in increments of 15 cm from 0 to 30 cm in depth at

judgmental locations beneath the floor of the Reactor Confinement Room (Room 131) and

reactor pool floor. Sampled locations corresponded to locations UVA made accessible during

decommissioning activities. Figure 2 shows the soil sampling locations.

EXTERIOR

ESSAP used the following procedures for outdoor portions of the survey area.

Reference Grid

Measurement and sampling locations were noted on a UVA-drawn figure of the exterior areas.

Surface Scans

Surface scans of outdoor locations, including soil areas where the underground waste tanks were

removed and the reactor pond, were performed over approximately 25 to 100% of the accessible

areas using a NaI scintillation detector coupled to a ratemeter.

University of Virginia Reactor 5 projects\0981\Reports\2005-08-08 Revised Final ReporLdoc

Soil Samplin2

Surface soil (0-15 cm) and sub-surface soil (in increments of 15 cm from 15 cm depth to 45 cm

depth) samples were collected at judgmental locations from the reactor pond. Figure 7 shows the

soil sampling locations.

On January 21, 2003, UVA collected soil samples from the waste tank excavation during an

NRC inspection. The soil samples were split and the NRC requested UVA to store the NRC's

samples until a future date. During this confirmatory survey, the NRC inspector requested that

ESSAP analyze a limited number of the split samples. ESSAP chose three of the split samples

for which UVA reported positive Cs-137 concentrations, and two additional samples were

selected randomly. It should-be noted that UVA did not maintain a record of the chain-of-

custody for the NRC's split samples; however, the samples were stored in a container within the

UVAR facility and security seals on all of the split samples were intact.

SAMPLE ANALYSIS AND DATA INTERPRETATION

Samples and data were returned to ORISE's ESSAP Oak Ridge, Tennessee, facility for analysis

and interpretation. Sample analyses were performed in accordance with the ORISE/ESSAP

Laboratory Procedures Manual (ORISE 2004d). Dry smear samples were analyzed for gross

alpha and gross beta activity using a low-background gas proportional counter. Smear results

and direct measurements for total surface activity were converted to units of disintegrations per

minute per 100 square centimeters (dpm/100 cm 2). Soil samples were analyzed by gamma

spectroscopy. Spectra were reviewed for identifiable total absorption peaks. Soil sample results

were reported in units of picocuries per gram (pCi/g).

Confirmatory survey data were compared with the appropriate regulatory guidelines for release

of the site without radiological restrictions. Predominant radionuclides of concern found at the

UVAR facility include Co-60 and Cs-137, with lesser amounts of C-14, Fe-55, and Eu-152. The

radionuclides present and their relative ratios varied depending on the mechanism of

contamination and the medium type. Research projects in labs M005 and M008 included the use

of Tc-99 and Ni-63.

University of Virginia Reactor 6 projects\0981\Reports\2005-08-08 Revised Final Report.doc

The UVAR facility derived concentration guideline levels (DCGL) for building surfaces were

selected from NRC tables of screening values published in NUREG-1757, Volume 1 (NRC

2003). UVA calculated a gross activity DCGL of 6,320 dpm/100 cm 2, except for laboratories

M005 and M008, based on Final Status Survey Plan Addendum 004, Appendix A. UVA

calibrated surface activity measurement instrumentation to Tc-99. The contamination in

laboratories M005 and M008 was Tc-99 and Ni-63, respectively. UVA selected the gross

activity DCGL of 1.3E6 dpm/100 cm 2, based on the more conservative screening value for

Ni-63, for these laboratories, and calibrated surface activity measurement instrumentation to

Ni-63. Because screening values were selected to demonstrate compliance, UVA elected to not

allow areas of elevated activity; therefore, there are no included area factors (UVA 2004a).

Appendix C provides the screening values published in NUREG-1757, Volume 1 (NRC 2003)

that UVA must meet for unrestricted release of soil areas. UVA modified these screening values

to account for hard to detect radionuclides. The following modified DCGLs are applicable:

3.4 pCi/g for Co-60 in soil from beneath the Reactor Confinement Room (Room 131) and reactor

pool as well as soil from the waste tank excavation and 5.9 pCi/g for Cs-137 for the reactor pond

soil. These guidelines apply to the upper 15 cm of soil in the waste tank excavation. They also

apply to the upper 0 to 1 m of soil from the reactor pond, the soil beneath the Reactor

Confinement Room (Room 131), and reactor pool. While soil samples could not be collected

down to a full depth of 1 m, the upper sub-surface soils collected represented areas with the

highest contamination potential that could be used to identify areas requiring further

investigation (UVA 2004a).

FINDINGS AND RESULTS

DocuMENT REVIEW

ESSAP reviewed the licensee's FSS plan (UVA 2004b) and report (UVA 2004a). Comments

ESSAP identified in the project documentation were provided to NRC/NRR (ORISE 2003 and

2004a). UVA's responses to the NRC's Request for Additional Information (RAI) were

reviewed and determined to be acceptable (ORISE 2005b). The procedures, methods, and data

University of Virginia Reactor 7 projects\0981Reports\2005-08-08 Revised Final Report.doc

submitted by UVA were considered to be appropriate and adequately documented the

radiological status of the UVAR facility.

INTERIOR

The results for interior surveys are discussed below.

Surface Scans

Three areas of elevated beta surface radiation were noted in the reactor pool. One area was

found on the lower portion of the gate frame, a second area was a debris pile found on the floor

on the northern side, and a third area was located on the southern side. UVA removed the debris

pile-follow-up scans did not note any residual elevated beta radiation. Five areas of elevated

beta surface radiation were noted in Room M008--each of these areas had been marked by

UVA. One area of elevated beta surface radiation was noted on a lower wall in the CAVALIER

facility (Room G007). One area of elevated gamma radiation at approximately eight times

background was noted in a partial floor core in the concrete of the northern side of the reactor

pool. After ESSAP's investigation, a hot particle was removed from the partial floor core. UVA

performed a gamma spectroscopy field measurement and identified the contaminant to be Co-60.

UVA hypothesized that this was a residual stainless steel "flea" from underwater cutting

operations performed in the 1980s. Two completed reactor floor bore holes had elevated gamma

radiation levels ranging from approximately four to eight times background--one borehole was

noted as number 10 in the UVA FSS documentation while the other was installed during

characterization per on-site discussion with UVA subcontractors. Scans of the remaining

surfaces did not identify any additional locations of elevated beta or gamma radiation.

Surface Activity Levels

Total and removable surface activity levels are provided in Table 1. Total beta activity levels

ranged from -240 to 33,000 dpm/100 cm2 for all areas., Removable activity levels ranged from

0 to 5 dpmr/100 cm 2 for gross alpha and from -5 to 30 dpm/100 cm2 for gross beta for all areas.

A summary of the total surface activity results for areas of interest is provided below and

includes the gross activity DCGL for each area.


UVAR Area Range of Total Beta Activity Gross Activity DCGL(dpm/100 cm2) (dprn/100 cm 2)

Reactor Confinement Room(Ro11 6 to 1,300 6,320(Room 131)

Reactor Pool 300 to 4,900 6,320Former HP Labs (Room -240 to 33,000 1E6M005, MO05A, and M008)Remaining Areas 230 to 2,500 6,320

Radionucide Concentrations in Soil Samples

Table 2 shows the radionuclide concentrations in soils beneath the Reactor Confinement Room

(Room 131) and reactor pool for Co-60, Cs-137, Eu-152, and Eu-154 identified during the

analysis of the soil samples by gamma spectroscopy. Radionuclide concentrations in the soilsranged from -0.04 to 2.98 pCi/g for Co-60, -0.02 to 0.12 pdi/g for Cs-137, -0.09 to 0.14 pCi/g

for Eu-152, and -0.12 to 0.17 pCi/g for Eu-154. Using the sum-of-fractions (SOF) calculation to

compare to the unity rule, as discussed in Section 4.3.3 of MARSSIM (NRC 2000), the SOF

values ranged from 0.00 to 0.92. In addition, elevated levels of natural thorium (by Ac-228) and

natural uranium (by Th-234) were noted in the reactor pool samples. Concentrations in samples

S0006 through S0009 ranged from 3.38 to 6.47 pCi/g for Ac-228 and 1.95 to 4.60 pCi/g for

Th-234.

EXTERIOR

The results for exterior surveys are discussed below.

Surface scans

Gamma surface scans were within the range of ambient background levels.

Radionuclide Concentrations in Soil Samples

Table 2 shows the radionuclide concentrations in soils collected from the reactor pond for Co-60,

Cs-137, Eu-152, and Eu-154 identified during the analysis of the soil samples by gamma

spectroscopy. Radionuclide concentrations in the soils ranged from 0.00 to 5.50 pCi/g for

Co-60, 0.00 to 1.67 pCi/g for Cs-137, -0.07 to 8.11 pCi/g for Eu-152, and -0.05 to 0.70 pCi/g for

Eu-154. The SOF values ranged from 0.00 to 2.8.

University of Virginia Rewwr 9 projects\0981\Reports\2005-08-08 Revised Final Reportdoc

Table 3 shows the radionuclide concentrations in the NRC's split soil samples from the waste

tank excavation for Co-60, Cs-137, Eu-152, and Eu-154 identified during analysis of the soil

samples by gamma spectroscopy. Radionuclide concentrations in the soils ranged from -0.01 to

0.01 pCi/g for Co-60, 0.13 to 0.32 pCi/g for Cs-137, -0.07 to 0.02 pCi/g for Eu-152, and -0.09 to

0.13 pCi/g for Eu-154. The SOF values ranged from 0.01 to 0.05. The reported data for UVA's

split samples are also reported in Table 3 and were comparable with the ESSAP results.

COMPARISON OF RESULTS WITH GUIDELINES

Results of the survey were compared to the applicable guidelines. Confirmatory results for

building surfaces were all less than the applicable gross activity DCGLs. One surface soil

sample from the reactor pond (0981S0012) exceeded the screening value for Co-60; because this

elevated area was not identified during surface scans and the activity exceeding the screening

value was only identified in the upper 15 cm of the soil, the sample is not indicative of a large,

distributed source but rather a small isolated area. Based on these results and an evaluation of

the licensee's data, it is ESSAP's opinion that the soil from 0 to 1 m would meet the individual

radionuclide DCGLs and the unity rule. All other confirmatory soil samples and split soil

samples from the waste tank excavation met individual radionuclide DCGLs as well as the unity

rule. The elevated gamma levels noted in two boreholes in the northern section of the reactor

pool floor were caused by the elevated natural thorium and uranium concentrations. These

elevated levels were expected for the area per discussions with the licensee staff.

SUMMARY

At the request of the U.S. Nuclear Regulatory Commission, the Environmental Survey and Site

Assessment Program of the Oak Ridge Institute for Science and Education conducted

confirmatory survey activities for the University of Virginia Reactor in Charlottesville, Virginia.

Confirmatory activities included document and data reviews, and during the period March 8 to

10, 2005, independent surface scans, surface activity measurements, and soil sampling.

University of Virginia Reactm 10 projects\0981\Reports\2005-08-08 Revised Final Report.doc

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The findings of the confirmatory survey support UVA's final survey results for building surfaces

and soil areas, and in ESSAP's opinion, indicate that the radiological conditions of the surveyed

areas satisfy the NRC guidelines for release without radiological restrictions.

University of Vixginia Rmtw 11 projects\98l\Reportsm\2005-08-O5 Revised Fimal Reportdoc

FIGURES

University of Virginia Reactor projects\0981Reports\2005-08-08 Revised Final Report.doc

981-001 (2)

NIr

NOT TO SCALE

FIGURE 1: Location of the University of Virginia, Charlottesville, Virginia


981-002 (2)

FIGURE 2: UVA Reactor First Floor - Measurement and Sampling Locations

University of Virginia Reactor 14 projects\0981•Reports\2005-08-08 Revised Final Reportdoc

981-003 (1)

4+0.3

4

3

2

1

0

7+0.

7

6

5

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I

MEASUREMENT/SAMPLINGLOCATIONS

* # SINGLE-POINTLOWER WALLS AND FLOOR

D SURVEYED AREA

N

NOT TO SCALE

I ________________________________ L

FIGURE 3: UVA Reactor Mezzanine Floor - Measurement and Sampling Locations


981-004 (1)

5340C

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A

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B C D E 0

ROOM G024

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ROOM G026

E E+0.5


LW# SINGL LAPOINTLOWER WALLS AND FLOOR

E SURVEYED AREA

k INACCESSIBLE AREA

N

NOT TO SCALE

FIGURE 4: UVA Reactor Ground Floor, East Areas - Measurement and Sampling Locations

University of Virginia Reactor 16 projects\0981\Reportso2005-08-08 Revised Final Report.doc

981-005 (1)

Rabbit Room

4-~U. ~ I--- - -

CAVALIERFacility 4

3

2

1

58 v6O58 60- -1- -

591

7.8

7

A B C D

ROOM G005

E E+0.75

6

4

3

2

0A B C D E F G H

ROOM 3007


# SINGLE-POINTLOWER WALLS AND FLOOR

l SURVEYED AREA

N

NOT TO SCALE

I I

FIGURE 5: UVA Reactor Ground Floor, West Areas - Measurement and Sampling Locations

University of Virginia Reactor 17 projects\098l\Reports\2005-08-08 Revised Final Report.doc

981-006 (1)

0

-1 - - - -

-2

-3

-4

-6

-7

-7-0.35A B C D ENorth Pool, North Wall

0

-1 - - - -

-2

-3

-4 -- -

-5 - 4

-6 26

-7-7-0.35 - _ 25

1-0.9 E+0.7 E D C B ANorth Pool, East Wall

0

-1

-2

-3

-4

-5

-6

-7-7-0.35

0

-1

-2

-3

-4

-5

-6

-7-7-0.35

6

,28

A B C D ENorth Pool, West Wall

3

1 i)20

A B C D ESouth Pool, West Wall

E+0.7

0

-I

-2

-3

-4

-5

-6

-7-I 15-

0

-1

-2

-3

-4

-5

-6

-7

2

-j17

7-S

-7-0.35A B C D E

South Pool, East Wall

-7-0.351 1E D C B A

South Pool, South Wall


# SINGLE-POINTLOWER WALLS AND FLOOR

A # SINGLE-POINTUPPER WALLS

[] SURVEYED AREA

N

NOT TO SCALE

FIGURE 6: UVA Reactor Ground Floor, Reactor Pool Walls - Measurement and Sampling Locations


981-006 (1)

SAMPLING LOCATIONS

* # SURFACE/SUBSURFACE SOIL

N

II

NOT TO SCALE

FIGURE 7: UVA Reactor Pond - Sampling Locations


TABLES


TABLE 1

SURFACE ACTIVITY LEVELSUNIVERSITY OF VIRGINIA REACTOR

UNIVERSITY OF VIRGINIACHARLOTTESVILLE, VIRGINIA

Locationa Surfaceb Total Beta Activity Removable Activity(dpm/100 cm 2) (dpm/1O0cm 2)

Alpha 7 -Beta

Reactor Confinement Room (Room 131)

39 F 1,300 0 -1

40 F 1,100 0 -2

41 F 820 0 1

42 F 320 1 3

43 F 450 3 7

44 F 890 0 9

45 LW 460 0 -3

46 LW 840 0 -4

47 LW 16 0 3

48 LW .170 0 -1

Reactor Pool

1 UW 1,200 __c --

2 UW 1,100 ..--

3 UW 840 ..--

4 UW 1,400 ..--

5 UW 1,100 ..

6 UW 1,200 -- --

13 F 1,900 0 -4

14 F 1,200 1 10

15 LW 890 0 -3

16 LW 1,200 0 6

17 LW 300 1 6

18 LW 1,800 1 -3

19 LW 1,800 0 -1

University of Virginia Reactor 21 projeets\0981\Reports\2005-O8-08 Revised Final Report.doc

TABLE 1 (Continued)



eb Total Beta Activity Removable ActivityLocationa Surface (dpm/100 cm2) (dpMIOOCM2 )

Alpha Beta

Reactor Pool - Continued

20 LW 1,100 0 2

21 F 4,400 1 5

22 F 2,100 0 7

23 LW 1,500 0 -2

24 LW 1,100 0 5

25 LW 1,500 0 3

26 LW 1,000 5 -1

27 F 4,900 0 6

28 LW 1,300 3 -5

Former HP Lab (Rooms M005 and M005A)

33 F -240 0 1

34 F 240 3 1

35 LW 790 1 -2

36 LW 1,000 0 6

37 F -48 1 -5

38 LW 790 0 -2

Former Hot Lab (Room M008)

29 F 210 3 1

30 F 2,100 3 3

31 LW 33,000 0 -1

32 LW 1,300 0 3

Demineralizer Room (Rooms M021 and M021A)

49 F 750 0 23

50 F 1,400 1 9

University of Virginia Reactor 22 projects\0981 Reports\2005-08-O8 Revised Final Report.doc

TABLE 1 (Continued)



I 17

Demineralizer Room (Rooms M021 and M021A) - Continued

51 F 490 0 3

52 F 700 1 3

Rabbit Room (Room G005)

58 F 360 0 -1

59 F 230 0 6

60 LW 870 1 2

CAVALIER Facility (Room G007)

55 F 390 0 2

56 F 1,100 0 -4

57 LW 2,500 0 7

Heat Exchanger Room (Room G024)

53 F 1,000 1 2

54 F 1,400 1 30

Hot Cell (Rooms G025, G026, and G027)

7 LW 1,000 0 4

8 F 1,100 0 -1

9 LW 260 1 1

10 F 1,300 3 1

11 LW 1,700 0 1

12 F 1,300 0 2

'Refer to Figures 2 through 6.bF = floor; LW = lower wall; UW = upper wall.F- = Measurement not performed.


TABLE2

RADIONUCLIDE CONCENTRATIONS IN SOILINTERIOR LOCATIONS AND REACTOR POND



ESSAP Sample Depth Radionuclide Concentration (pCi/g) SOFbNumber' (cm) I Co-60 Cs-137 Eu-152 Eu-154

Fill Beneath Reactor Confinement Room Floor (Room 131)

0981S0001 0-15 -0.02 ± 0.03c 0.02 ± 0.03 0.01 ±0.06 0.11 ±0.13 0.02

0981S0002 0-15 0.12 ± 0.06 0.91 ± 0.04 -0.01 ± 0.06 0.03 ± 0.13 0.04

0981S0003 15-30 0.08 ± 0.05 0 .0 0 d + 0.02 0.02 ± 0.06 -0.12 ± 0.12 0.03

0981S0004 0-15 0.03 ± 0.03 0.00 ± 0.02 -0.05 ± 0.05 0.00 ± 0.10 0.01

0981SO005 15-30 0.00 ± 0.03 -0.01 ± 0.03 -0.01 ± 0.06 0.05 ± 0.13 0.01

Soil Beneath Reactor Pool Floor

0981S0006 0-15 0.00±0.04 0.02 ± 0.04 -0.11 ±0.09 0.06 ± 0.16 0.01

0981S0007 15-30 -0.04 ± 0.05 -0.02 ± 0.04 -0.09 ± 0.09 -0.01 ± 0.19 0.00

0981S0008 0-15 2.98 ±0.14 0.12 ± 0.03 0.14 ±0.09 0.17 ±0.14 0.92

0981S0009 15-30 0.70 ±0.10 0.03 ± 0.04 0.10 ±0.09 -0.11 ±0.17 0.22

Reactor Pond

0981S0010 0-15 0.04±0.05 0.12 ± 0.03 -0.03 ± 0.08 0.05 ±0.15 0.04

0981S0011 15-30 0.00 ± 0.03 0.00 ± 0.03 -0.07 ± 0.07 -0.05 ± 0.15 0.00

0981S0012 0-15 5.50 ± 0.25 1.67 ± 0.13 8.11 ±0.43 0.70 ± 0.30 2.8

0981S0013 15-30 0.32 ± 0.09 0.55 ± 0.06 0.30 ± 0.09 0.27 ± 0.20 0.25

0981S0014 0-15 0.03 ± 0.05 1.05 ± 0.07 -0.01 ± 0.07 -0.03 ±0.14 0.19

0981S0015 15-30 0.03 ± 0.04 0.18 ± 0.06 0.05 ± 0.09 -0.04 ±0.16 0.04

0981S0016 30-45 0.01 ± 0.04 0.08 ± 0.04 -0.05 ± 0.07 0.03 ± 0.16 0.02

"Refer to Figures 2 and 7.bCalculated using the sum-of-fractions (SOF) to compare to the unity rule, as discussed in Section 4.3.3 of MARSSIM(NRC 2000). Refer to Appendix C for surface soil screening DCGLs. To account for hard to detect radionuclides, UVA appliedthe following modified DCGLs: 3.4 pCi/g Co-60 in soil beneath the Reactor Confinement Room (Room 131) and reactor poolfloor and 5.9 pCi/g Cs-137 for the reactor pond.

*Uncertainties are total propagated uncertainties at the 95% confidence level.dZero values are due to rounding.

University of Virginia Reactor 24 projects\O981lReports\2O05-08-08 Revised Final Report.doc

, - - -, - - -, -- - ~- -,-.' q~ - 4F 1 r '.- . -

01

TABLE 3

RADIONUCLIDE CONCENTRATIONS IN SOILSPLIT SAMPLES FROM THE WASTE TANK EXCAVATION



ESSAP ESSAP Radionuclide Concentration (pCi/g) UVA Sample UVA Radionuclide Concentration (pCi/g)bSample SOF4 IDNumber Co-60 Cs-137 Eu-152 Eu-154 Co-60 Cs-137

0981S0017 0.01 ± 0.03c 0.19 ± 0.04 0.02 ± 0.06 -0.07 ± 0.12 0.02 N.VA-WTFS- <0.16 <0.31N3.6-W23.7

0981SO018 -0.01 ± 0.04 0.15 ± 0.05 -0.06 ± 0.07 0.04 ± 0.16 0.02 UVA-WTFS1 <0.21 0.28N3.6-W18.7

0981S0019 0.01 ± 0.03 0.13 ± 0.04 -0.04 ± 0.06 -0.04 ± 0.20 0.01 UVA-WTFS- <0.12 0.1N0.7-WT1.2

0981S0020 0.01 ± 0.04 0.32 ± 0.05 -0.07 ± 0.07 0.13 ± 0.14 0.05 UVA-WTFS- <0.26 0.56NO.7-W21.2

0981S0021 0.00" ± 0.04 0.27 ± 0.05 -0.06 ± 0.07 -0.09 ±0.15 0.02 UVA-WTFS- <0.19 0.461 1 11 1 1NO.7-W6.2

'Calculated using the sum-of-fractions (SOF) to compare to the unity rule for the ESSAP data, as discussed in Section 4.3.3 of MARSSIM (NRC 2000). Refer to Appendix C forsurface soil screening DCGLs. To account for hard to detect radionuclides, UVA applied a modified DCGL of 3.4 pCi/g Co-60.

bUVA data from Table 4-2 of the Final Status Survey Report, Revision 1 (UVA 2004a).'Uncertainties are total propagated uncertainties at the 95% confidence level.dZero value is due to rounding.

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REFERENCES

Oak Ridge Institute for Science and Education (ORISE). Document Review-Master FinalStatus Survey Plan and Addendums 001-008, University of Virginia, Charlottesville, Virginia[Docket No. 50-62; Task No. 2.1]. Oak Ridge, TN; October 24, 2003.

Oak Ridge Institute for Science and Education. Document Review-Final Status SurveyDocumentation, University of Virginia, Charlottesville, Virginia [Docket No. 50-62; Task No.2.2]. Oak Ridge, TN; July 12, 2004a.

Oak Ridge Institute for Science and Education. Survey Procedures Manual for theEnvironmental Survey and Site Assessment Program. Oak Ridge, Tennessee; September 2,2004b.

Oak Ridge Institute for Science and Education. Quality Assurance Manual for the EnvironmentalSurvey and Site Assessment Program. Oak Ridge, Tennessee; August 31, 2004c.

Oak Ridge Institute for Science and Education. Laboratory Procedures Manual for theEnvironmental Survey and Site Assessment Program. Oak Ridge, Tennessee; August 31, 2004d.

Oak Ridge Institute for Science and Education. Final Confirmatory Survey Plan for theUniversity of Virginia Research Reactor, University of Virginia, Charlottesville, Virginia[Docket No. 50-62; Task No. 2.8]. Oak Ridge, TN; February 28, 2005a.

Oak Ridge Institute for Science and Education. Review of UVA Responses to NRC RAIs. OakRidge, TN; January 20, 2005b.

U.S. Nuclear Regulatory Commission (NRC). Multi-Agency Radiation Survey and SiteInvestigation Manual (MARSSIM). Washington, DC: NUREG-1575, Revision 1; August 2000.

U.S. Nuclear Regulatory Commission. Consolidated NMSS Decommissioning Guidance:Decommissioning Process for Materials Licensees. Washington, DC: NUREG-1757, Volume 1,Revision 1; September 2003.

University of Virginia (UVA). University of Virginia Decommissioning Plan. Charlottesville,VA; February 2000.

University of Virginia. Final Status Survey Report, Revision 1. Charlottesville, VA; November2004a.

University of Virginia. Master Final Status Survey Plan, UVA-FS-002. Charlottesville, VA;Revision 1, April 2004b.

University of Virginia Reactor 26 projects\0981lReports\2005-08-08 Revised Final Report.doc

APPENDIX A

MAJOR INSTRUMENTATION


APPENDIX A

MAJOR INSTRUMENTATION

The display of a specific product is not to be construed as an endorsement of the product or itsmanufacturer by the author or employer.

SCANNING INSTRUMENT/DETECTOR COMBINATIONS

Alpha-Beta

Ludlum. Floor Monitor Model 239-1combined withLudlum Ratemeter-Scaler Model 2221coupled toLudlum Gas Proportional Detector Model 43-37, Physical Area: 550 cm2

(Ludlum Measurements, Inc., Sweetwater, TX)

Ludlum Ratemeter-Scaler Model 2221coupled toLudlum Gas Proportional Detector Model 43-68, Physical Area: 126 cm2


Gamma

Eberline Pulse Ratemeter Model PRM-6(Eberline, Santa Fe, NM)coupled toVictoreen Nal Scintillation Detector Model 489-55, Crystal: 3.2 cm x 3.8 cm(Victoreen, Cleveland, OH)

Ludlum Model 12(Ludlum Measurements, Inc., Sweetwater, TX)coupled toVictoreen NaI Scintillation Detector Model 489-55, Crystal: 3.2 cm x 3.8 cm(Victoreen, Cleveland, OH)

DIRECT MEASUREMENT INSTRUMENT/DETECTOR COMBINATIONS

Beta

Ludlum Ratemeter-Scaler Model 2221coupled toLudlum Gas Proportional Detector Model 43-68, Physical Area: 126 cm2


University of Virginia Reactor A-1 projects\0981lReports\2005-08-08 Revised Final Report.doc

LABORATORY ANALYTICAL INSTRUMENTATION

Low Background Gas Proportional CounterModel LB-5100-W(Oxford, Oak Ridge, TN)

High Purity Extended Range Intrinsic DetectorCANBERRA/Tennelec Model No: ERVDS30-25195(Canberra, Meriden, CT)Used in conjunction with:Lead Shield Model G-1 1(Nuclear Lead, Oak Ridge, TN) andMultichannel AnalyzerDEC ALPHA Workstation(Canberra, Meriden, CT)

High Purity Extended Range Intrinsic DetectorModel No. GMX-45200-5(AMETEK/ORTEC, Oak Ridge, TN)used in conjunction with:Lead Shield Model SPG-16-K8(Nuclear Data)Multichannel AnalyzerDEC ALPHA Workstation(Canberra, Meriden, CT)

High-Purity Germanium DetectorModel GMX-30-P4, 30% Eff.(AMETEK/ORTEC, Oak Ridge, TN)Used in conjunction with:Lead Shield Model G-16(Gamma Products, Palos Hills, IL) andMultichannel AnalyzerDEC ALPHA Workstation(Canberra, Meriden, CT)

University of Virginia Reactor A-2 projects\0981\Reports\2005-08-08 Revised Final Reportdoc

APPENDIX B

SURVEY AND ANALYTICAL PROCEDURES

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University of Virginia Reactor projects\O981\Reports\2005-08-08 Revised Final Report.doc

APPENDIX B

SURVEY AND ANALYTICAL PROCEDURES

PROJECT HEALTH AND SAFETY

The proposed survey and sampling procedures were evaluated to ensure that any hazards

inherent to the procedures themselves were addressed in current job hazard analyses (JHAs). All

survey and laboratory activities were conducted in accordance with ORISE health and safety and

radiation protection procedures.

A walkdown of the survey areas was performed in order to evaluate and identify potential health

and safety issues. UVA provided general site-specific safety awareness-falls into the floor

openings were of the greatest concern. Survey work was performed per the ORISE generic

health and safety plans, a site-specific integrated safety management (ISM) pre-job hazard

checklist, and the safety procedures discussed during the training.

QUALITY ASSURANCE

Analytical and field survey activities were conducted in accordance with procedures from the

following documents of the Environmental Survey and Site Assessment Program:

" Survey Procedures Manual, (September 2004)

" Laboratory Procedures Manual, (August 2004)

" Quality Assurance Manual, (August 2004)

The procedures contained in these manuals were developed to meet the requirements of

Department of Energy (DOE) Order 414.1B and the U.S. Nuclear Regulatory Commission

Quality Assurance Manual for the Office of Nuclear Material Safety and Safeguards and contain

measures to assess processes during their performance.

Quality control procedures include:

" Daily instrument background and check-source measurements to confirm that equipment

operation is within acceptable statistical fluctuations.

" Participation in MAPEP, NRIP, and ITP Laboratory Quality Assurance Programs.

University of Virginia Reactor B-1 projects\0981\Reports\2005-08-08 Revised Final Reportdoc

* Training and certification of all individuals performing procedures.

* Periodic internal and external audits.

CALIBRATION

Calibration of all field and laboratory instrumentation was based on standards/sources, traceable

to NIST, when such standards/sources were available. In cases where they were not available,

standards of an industry-recognized organization were used.

Detectors used for assessing surface activity were calibrated in accordance with ISO-7503 1

recommendations. The total efficiency (-total) was determined for each instrument/detector

combination and consisted of the product of the 2n instrument efficiency (Ei) and surface

efficiency (Fs): etota =- Ei x F,.

UVA selected Tc-99 as the calibration source (maximum beta energy of 292 keV) as it provides

a conservative representation of the radionuclide mixture for all areas except Rooms M005 and

M008 where Ni-63 was the chosen calibration source. ISO-7503 recommends an Es of 0.25 for

beta emitters with a maximum energy of less than 0.4 MeV (400 keV) and an F of 0.5 for

maximum beta energies greater than 0.4 MeV. UVA selected an F, of 0.25 in order to calculate a

conservative cttal. UVA calibrated their hand-held gas-proportional instrumentation using a

0.8 mg/cm2 Mylar window for all areas except laboratories M005 and M008 where a 0.4 mg/cm2

window was used. ESSAP calibrated instruments for the confirmatory survey using the same

methodology and detector window configuration as UVA.

Surface Scans

Hand-held detectors were placed on contact with the calibration sources. A postulated hot-spot

size of 100 cm2 was assumed a priori for determining scanning instrument efficiencies. The

scanning Fi values were 0.47 and 0.18 for Tc-99 and Ni-63, respectively, for the hand-held gas

proportional detectors; the calculated scanning E-,o values were 0.12 and 0.05 for Tc-99 and Ni-

lInternational Standard. ISO 7503-1, Evaluation of Surface Contamination - Part 1: Beta-emitters (maximum betaenergy greater than 0.15 MeV) and alpha-emitters. August 1, 1988.


63, respectively. Calibration source emission rates were not corrected for geometry when

sources larger than the detectors were used.

The scanning Fto was determined for the floor monitor in the same fashion as above for the

hand-held gas proportional detectors except typical efficiencies for the floor monitor were used

rather than specific calibrations for this survey. The scanning Ei for Tc-99 was 0.24; the

scanning stotw was 0.06.


The calibration F, values for the hand-held gas proportional detectors used for the confirmatory

survey were 0.39 and 0.18 for Tc-99 and Ni-63, respectively. Calibration source emission rates

were corrected to the active area of the detector when the calibration source area exceeded the

detector area. The static etow values used were 0.10 and 0.05 for Tc-99 and Ni-63, respectively.

SURVEY PROCEDURES

Surface Scans

Surface scans were performed by passing the detectors slowly over the surface; the distance

between the detector and the surface was maintained at a minimum - nominally about 1 cm. A

large surface area, gas proportional floor monitor with a 0.8 mg/cm2 window and a NaI

scintillation detector was used to scan the floors of the surveyed areas. Wall surfaces were

scanned using small area (126 cm 2) hand-held detectors with a 0.8 mg/cm2 window. For Rooms

M005 and M008, hand-held detectors with 0.4 mg/cm2 windows were used to scan the floors,

walls, and ceilings. Identification of elevated levels was based on increases in the audible signal

from the recording and/or indicating instrument.

Scan minimum detectable concentrations (MDCs) were estimated using the calculational

approach described in NUREG-15072 . The scan MDC is a function of many variables, including

the background level. Site beta background levels were within the typical range of 800 to 1,400

cpm for the large area gas proportional detectors (floor monitors) and 250 to 450 cpm for the

2NUREG- 1507. Minimum Detectable Concentrations with Typical Radiation Survey Instruments for VariousContaminants and Field Conditions. US Nuclear Regulatory Commission. Washington, DC; June 1998.

University of Virginia Reactor B-3 projects\0981lReports\2005-08-08 Revised Final Report.doc

hand-held gas proportional detectors. Additional parameters selected for the calculation of scan

MDC included a one-second observation interval, a specified level of performance at the first

scanning stage of 95% true positive rate and 25% false positive rate, which yields a d' value of

2.32 (NUREG-1507, Table 6.1), and a surveyor efficiency of 0.5. To illustrate an example for

the hand-held gas proportional detectors with 0.8 mg/cm 2 windows, the minimum detectable

count rate (MDCR) and scan MDC can be calculated as follows:

bi = (250 cpm) (1 s) (1 min/60 s) = 4.2 counts

MDCR = (2.32) (4.2 counts)½ [(60 s/min) / (1 s)] = 285 cpm

MDCRsu-veyor = 285 1(0.5) Y = 403 cpm

The scan MDC is calculated using the total scanning efficiency (ctotai) of 0.12:

Scan MDC = MDCRsunveyor dpm/100 cm 2

etota

The scan MDC was calculated to be 3,400 dpm/100 cm 2. For the given background ranges, the

following table summarizes the calculated scan MDC values.

Detector Scan MDC Range (dprn/100 cmr)0.8 m•m/cm 2 Window 0.4 mg/cm2 Window

Hand-Held Gas Proportional 3,300 to 4,500 8,000 to 11,000Floor Monitor 12,000 to 16,000 N/Aa

a Not applicable

The scan MDCs for the NaI scintillation detector for the contaminants of concern in surface soil

were obtained directly from NUREG-1507 when available. The scan MDCs provided in

NUREG-1507 were 5.8 and 10.4 pCi/g, respectively, for Co-60 and Cs-137. For Eu-152 in soil,

the scan MDC was approximately 5.8 pCi/g3. The scan MDCs for other major gamma-emitting

contaminants of concern were not provided in NUREG-1507. In such a case, it is standard

procedure for ESSAP staff to pause and investigate any locations where gamma radiation is

distinguishable from background levels.

3The scan MDC for Eu-152 was estimated based on empirical calculations for Nal response versus gamma energyprovided in Decommissioning Health Physics: A Handbook for MARSSIM Users, E.W. Abelquist; 2001.



Surface activity measurements were performed on poured concrete, cinderblocks, tile, wall

board, and corrugated metal. To account for the ambient gamma background, unshielded and

shielded measurements were performed at each location. A 3/8-inch Plexiglas shield was used to

determine the gamma count rate associated with the unshielded count rates. This thickness was

demonstrated to block the beta particles from Sr-90, including the beta particles from the

progeny Y-90. Since Y-90 emits beta particles higher in energy than Cs-137, the Plexiglas

shield completely shielded measurement of the Cs-137 beta emissions. Surface activity was

calculated by determining the net count rate, subtracting the shielded measurement from the

unshielded measurement, then correcting for total efficiency and detector area size.

The static beta MDCs--calculated using the calibration check-out count rate-for the gas

proportional detectors used for direct measurements are shown in the table below. The physical

surface area assessed by the gas proportional detector used was 126 cm2.

Detector Window Calibration Check-Out Static MDC(mg/cm2 ) Count Rate (cpm) (dpm/100 cm2)

0.4 392 1,5000.8 380 740

Removable Activity Measurements

Removable gross alpha and gross beta activity levels were determined using numbered filter

paper disks, 47 mm in diameter. Moderate pressure was applied to the smear and approximately

100 cm 2 of the surface was wiped. Smears were placed in labeled envelopes with the location

and other pertinent information recorded.

RADIOLOGICAL ANALYSIS

Gross Alpha/Beta

Smears were counted for two minutes on a low-background gas proportional system for gross

alpha and beta activity. The MDCs of the procedure were 9 dpm/100 cm 2 and 15 dpm/100 cm 2

for gross alpha and gross beta, respectively.

University of Virginia Reactor B-5 projects\0981\Reports\2005-08-08 Revised Final Report.doc

Gamma Spectroscopy

Samples of soil were dried, mixed, crushed, and/or homogenized as necessary, and a portion

sealed in a 0.5-liter Marinelli beaker or other appropriate container. The quantity placed in the

beaker was chosen to reproduce the calibrated counting geometry. Net material weights were

determined and the samples counted using intrinsic germanium detectors coupled to a pulse

height analyzer system. Background and Compton stripping, peak search, peak identification,

and concentration calculations were performed using the computer capabilities inherent in the

analyzer system. All total absorption peaks (TAP) associated with the radionuclides of concern

were reviewed for consistency of activity. Total absorption peaks used for determining the

activities of radionuclides of concern and the typical associated MDCs for a one-hour count time

were:

Radionuclide TAP (MeV) MDC (pCi/g)Co-60 1.173 0.05Cs-137 0.662 0.05Eu-152 0.344 0.11Eu-154 0.723 0.13

Spectra were also reviewed for other identifiable TAPs.

DETECTION LIMITS

Detection limits, referred to as minimum detectable concentration (MDC), were based on 3 plus

4.65 times the standard deviation of the background count [3 + (4.65$tBKG)]. Because of

variations in background levels, measurement efficiencies, and contributions from other

radionuclides in samples, the detection limits differ from sample to sample and instrument to

instrument.


40

4040

10

10

APPENDIX C

SUMMARY OF SURFACE SOIL SCREENING VALUES


APPENDIX C

SUMMARY OF SURFACE SOIL SCREENING VALUES

The following table lists the contaminants of concern and their associated surface soil screeningvalues published in NUREG-1757, Volume 11.

Radionucide Guideline Value (pCi/g)H-3 110

Fe-55 10,000Pu-239/240 2.3U-233/234 13.0

U-238 14.0Ni-59 5,500

Cs-134 5.7Cs-137 11.0Co-60 3.8

Eu-152 8.7Eu-154 8.0Mn-54 15.0

Ag-110m 3.9Zn-65 6.2Sr-90 1.7C-14 12.0Ni-63 2,100Tc-99 19.0

'U.S. Nuclear Regulatory Commission. Consolidated NMSS Decommissioning Guidance: DecommissioningProcess for Materials Licensees. Washington, DC: NUREG-1757, Volume 1, Revision 1; September 2003.

University of Virginia Reactor C-1 projects\0981\Reports\2005-08-08 Revised Final Reportdoc

Documents

Revised Final Report - Confirmatory Survey of the ...job hazard analysis kiloelectron volt kilometer square meter Mixed Analyte Performance Evaluation Program ... radiation research,